The unwanted death of cells through apoptosis or necrosis can be a fundamental cause of cardiac disease in humans. Although apoptosis is a discrete, tightly controlled process that is physiologically necessary for the select deletion of cells, necrosis is an ill-defined cascade of events that leads to cell rupture and inflammation. While the molecular mechanisms that promote apoptosis have been extensively defined, relatively little is understood of the molecular regulators of necrosis, despite the fact that this later form of cell death likely plays a much more prominent role in human cardiac disease (ischemic/reperfusion injury, heart failure, diabetic cardiomyopathy, anti-cancer agent-induced cardiotoxicity, etc.). Our long-range goal is to identify and fully characterize the molecular regulatory proteins that drive necrotic cell death so that they can be targeted for the treatment of adult cardiac disease. While necrosis can appear to be an unregulated process, it is actually highly regulated at the level of the mitochondria where swelling and loss of ATP generation are often the first definable events. For example, we have shown that specific, protein-mediated alterations within mitochondria function as critical events in the initiation of necrotic death. Thus, our central hypothesis is that, rather than being an uncontrolled, non-specific process, necrosis is in fact mediated/initiated by specific molecular components that are mitochondrial-dependent. The objective of the present application, therefore, is aimed at identifying critical proteins that mediate necrotic cell death, and to characterize a number of interesting candidate proteins that have already been identified. We have employed a highly innovative, combinatorial approach to identify the molecular circuitry of necrosis that ranges from biochemical approaches to studies in vertebrate animal models. The rationale for the proposed research is that once key proteins that mediate necrosis are identified, they can be targeted as a means of treating a whole array of human cardiac diseases. PUBLIC HEALTH RELEVANCE The death of heart cells is an underlying cause of human heart disease. The proposed research is aimed at uncovering the molecular mechanisms that lead to heart cell death. Once the key proteins that mediate cell death are identified, they can then be targeted as a means of treating patients with heart disease.